Artificial hand



June 12, 195] w DRENNQN 2,556,524

ARTIFICIAL HAND Filed March 14, 1949 FIG I.

FIG. 2.

FIG. 3. 4e

INVENTOR WILLIAM M. DRENNON ATTORNEYS Patented June 12, 1951 UNITED STATES ATENT OFFHQE 6 Claims.

This invention relates to improvements in artificial hands.

It is among the objects of my invention to provide an artificial hand which simulates the human hand as nearly as possible both in appearance and in operation.

It is another object to provide, in an artificial hand, a novel and efficient segmental finger construction which renders the fingers easily operated, quite flexible and capable of grasping an object with substantial strength.

A further object is to provide an artificial hand construction in which the segments comprising the fingers are readily operable to grasp an object ,7 but are resiliently held against rotative movement relative to each other.

Another object is to provide an artificial hand construction wherein the efiiciency and durability of the hand are materially enhanced by providing a substantially rigid hollow body portion for the hand, to which relatively movable finger segments are flexibly attached :by means of springs extending through the segments, the springs providing hinges for the segments. Between the contiguous segments of each pair I preferably provide a spacer and guide element through which the springs and operating member extend. Actuating wires lead from the endmost segments through the other segments and spacers to the body and are there connected to a lever mechanism, from which a wire or chain leads up the sleeve of the user to be anchored at the shoulder. Thus, by moving the hand as a unit relative to the fist anchorage, the latter wire is placed under tension which causes the fingers to constrict about an object in the palm of the artificial hand. A flexible sheathing or glove, such as leather, rubber, or any suitable plastic material, covers the entire hand.

For instance, without intending to limit my invention in its broader aspects to such specific structure or embodiment, I illustrate in the accompanying drawings and will now describe a particular embodiment which I at present prefer. In the drawings:

Fig. l is a top plan view of an artificial hand embodying one example of my invention, parts being broken away and some parts being sectioned for illustrative purposes;

Fig. 2 is a side elevation with some parts being broken away and some sectioned for illustrative purposes;

Figs. 3, 4 and 5 are sectionalviews taken on lines 33, 44 and 5--5, respectively, of Fig. 2;

and I Fig. 6 is an enlarged fragmentary elevatio of the locking mechanism.

Referring now to the drawings, I show a glove or sheathing 5 which I prefer to make of a flexible leather, although other materials may be used for the purpose, such as rubber or a suitable plastic. The glove is hand shaped, providing four finger portions 5a, 5b, 5c and 5d, and a thumb portion 56.

The glove fits upon and encloses the finger segments to be described, as well as a rigid body I having an inner cavity 8 to house the operating mechanism to be hereinafter described.

Within each of the finger portions 50, Ed, I mount a plurality of segments l0, ll, l2. As best shown in Figs. 2 and 3, the segments I!) and l l are tapered towards the palm of the hand while the inner end surface of the tip segment I 2 is correspondingly beveled at [2a. Each of the segments l0, H has a pair of transversely spaced parallel, longitudinal holes l6, and a relatively large lower hole E8, which holes extend through the respective segments. The tip segment I 2 has two holes or sockets 2E! registering with holes Hi;

and a socket 2i registering with hole l8.

A spacer and guide member 25 is interposed between contiguous segments. Each of the members 25 has a pair of holes 21 (Fig. 4) registering, with holes l6, and a lower hole 29 registering with hole IS.

The other two finger portions 5a, 5b preferably do not contain segments such as before described, but each of those finger portions is filled by a relatively rigid integral part of the body extending into them, so that those fingers are stationary and have the shape of the other fingers when the latter are in the open position shown in Fig. 2. Of course, it is within the purview of my invention to make the fingers 5a and 5b of the construction of fingers 5c and. 511.

To urge the segments of fingers 5c, 50'! into the object grasping position shown in Fig. 2, I provide in each of those fingers a pair of coil springs 39, the inner end of each of those springs being anchored in a socket 32 in the body and the outer end being anchored in the socket 20 in the tip segment, the respective springs extendin through openings it in the intervening segments and through the holes 29 in the members 25. The spring is prestressed to draw the segments towards the body 1 and thus urge them into the object grasping position of Fig. 2.

A wire 35 is anchored at its outer end in socket 2| in the tip segment l2 and extends through openings 18, 29. To mount the anchor element 37 I provide a socket 3B in the tip segment and then, after effecting the anchor, fill the socket as by a plug 39.

Referring now to the thumb, its inner core portion id is rigid with the body l, having a beveled outer end surface 46a. lhe tip segment 42 has a pair of parallel sockets or openings 43 which register with openings 34 in portion 4B. A pair of coil springs 46 are anchored at their respective ends in the body and in the tip segment 42 and extend through openings 44 as well as through the openings 2! in the spacer and guide member 25a, which is like the previously described members 25. An operating wire 50 is anchored at its outer end in a socket 52 in the tip segment 32, extends through the opening 25 in the member 25a, and through an opening 54 in the portion it.

The operating linkage will now be described. A bracket 63 is fixed to the body by means of a screw ti and has a lever 62 pivoted thereto at 53. As shown in Fig. l, the bracket 68 has additional pivot holes 53a, 63b to permit adjustment by selectively placing the pivot pin in either of the holes.

A bifurcated link 65, pivoted at Efia on the lever 52, has its opposite end 6517 bifurcated to accommodate a T-shaped equalizer link $5. The cross portion Elia of the link 66 is provided at its ends with openings to receive the ends of the wires 35, the portion 65b of the link 66, having a similar opening to receive the end Of the wire 517. With this arrangement, a pulling force on the wire it will actuate the links 65 and 65 to effect a uniform tension on each of the wires 35 and 59.

From the free end of the lever 62 a wire 79 leads through the wrist portion TI and preferably is passed up the sleeve of the wearer and anchored in any suitable manner at the shoulder.

From the foregoing it will be apparent that by moving the hand as a unit, with the opposite end of the Wire fixed, the lever 62 is swung to the left, causing the linkage to pull on the wires 35 and wire 5%, to draw the fingers and thumb towards each other, so that an article held in 55 the palm of the hand may be firmly grasped.

As best seen in Figs. 1 and 6, I provide means for releasably locking the fingers and thumb in object grasping position, the parts being shown in unlocked position in Fig. 1 and in locked po- 60 sition in Fig. 6. A resilient bar is fixed at its left-hand end to the body as by screw it, and its outer end is formed as a rack l7. Normally the resiliency of the bars maintains the rack portion in the position of Fig. 1, out of engagement with the pawl to be described, but by manually pressing downwardly on the plunger 19, which reciprocates through a hole 8%! in the body, the rack portion is forced into the position of Fig. 6. The head 8| of the plunger is countersunk and may underlie the sheathing 5, which is flexible, so that the user, by pressing downwardly on that area of the sheathing, may operate the plunger.

As best shown in Fig. 6, the free end of the lever 62 has a pawl 85 mounted thereon by a 4 pivot 65, the pawl being urged clockwise by a spring 8?. Thus, when the rack is in the position of Fig. 5, the pawl will engage the teeth of the rack and will be retained in such engagement 5 by the stress placed on the lever through the finger and thumb operating wires. To release the pawl, the user merely moves the hand as a unit to place imther momentary tension on the wire NJ, at which time the rack portion Tl will auto- 10 matically spring back into the position of Fig. 1.

I claim:

1. In an artificial hand, a hollow body, a thumb and a finger projecting forwardly from the body, said finger being comprised of aligned relatively l5 movable segments, each of which is wedge-shaped in longitudinal section and has a plurality of -parallel longitudinal openings through its relatively wider top portion and a longitudinal hole through its narrower bottom portion, the openings in each segment being in register with the respective openings in the other segments and the hole in each segment being in register with the holes in the other segments, an elongated flexible tie member extending through each group of aligned openings, each said flexible tie member being anchored at one end to the outer endmost segment and anchored at its other end to the body, a flexible pull member extending through said registering holes, said pull member being anchored at its outer end to said outer endmost segments, and operating means in the body secured to the inner end of the pull member.

2. In an artificial hand, a hollow body, a thumb and a finger projecting forwardly from the body,

said finger being comprised of aligned relatively movable segments, each of which is wedgeshaped in longitudinal section and has a plurality of parallel longitudinal openings through its relatively wider top portion and a longitudinal hole through its narrower bottom portion, the openings in each segment being in register with the respective openings in the other segments and the hole in each segment being in register with the holes in the other segments, a coil spring ex tending through each group of aligned openings, each said coil spring being anchored at one end to the outer endmost segment and anchored at its other end to the body, a flexible pull member extending through said registering holes, said pull member being anchored at its outer end to said outer endmost segment, and operating means in the body secured to the inner end of the pull member.

3. In an artificial hand, a hollow body, a thumb and a finger projecting forwardly from the body, said finger being comprised of aligned relatively movable segments, each of which is wedge-shaped in longitudinal section and has a longitudinal opening through its relatively under top portion and a longitudinal hole through its relatively narrower bottom portion, said opening and said hole in each segment being in register with the opening and hole in each of the other segments, a fiat spacer block interposed between 65 each pair of contiguous segments, each block having an opening and a hole registering with said opening and hole in each of the contiguous segments, an elongated flexible tie member extending through said registering openings, said 0 tie member being anchored at its outer end to the outer endmost segment and anchored at its inner end to the body, a flexible pull member anchored to the outer endmost segment and extending through said registering holes into the body, and tension exerting means in the body connected to the inner end of the pull member.

4. In an artificial hand, a hollow body, a thumb and a finger projecting forwardly from the body, said finger being comprised of aligned relatively movable segments, each of which is wedge-shaped in longitudinal section and has a longitudinal opening through its relatively under top portion and a longitudinal hole through its relatively narrower bottom portion, said opening and said hole in each segment being in register with the opening and hole in each of the other segments, a spacer block interposed between each pair of contiguous segments, each block having parallel end surfaces and having an opening and a hole registering with said opening and hole in each of the contiguous segments, an elongated flexible tie member extending through said registering openings, said tie member being anchored at its outer end to the outer endmost segment and anchored at its inner end to the body, a flexible pull member anchored to the outer endmost segment and extending through said registering holes into the body, and tension exerting means in the body connected to the inner end of the pull member.

5. In an artificial hand, a hollow body, a thumb and a finger projecting forwardly from the body, said finger being comprised of aligned relatively movable segments, each of which is wedge-shaped in longitudinal section and. has a plurality of parallel longitudinal openings through its relatively wider top portion and a longitudinal hole through its narrower bottom portion, the openings in each segment being in a register with the respective openings in the other segments and the hole in each segment being in register with the holes in the other segments, an elongated flexible tie member extending through each group of aligned openings, each end to the outer endmost segment and anchored at its other end to the body, a flexible pull member extending through said registering holes, said pull member being anchored at its outer end to said' outer endmost segments, operating means in the body secured to the inner end of the pull member, and a flexible glove enclosing said body, thumb and fingers.

6. In an artificial hand, a hollow body, a thumb and fingers projecting forwardly from the body, the thumb and fingers each being composed of separate, relatively movable substantially aligned segments whose contiguous ends are beveled toward the palm to provide a wedgeshaped recess between each pair of contiguous segments, a spacer member having parallel end surfaces interposed between each pair of contiguous segments, a pair of resilient tie members extending through and drawing the wider portions of each group of substantially aligned segments with the spacer members interposed therebetween toward the body, flexible pull means anchored to the respective outer endmost of the segments and extending through the narrower portions of each group of substantially aligned segments and through the spacer members interposed therebetween into the body and tension exerting means in the body connected to the pull means.

WILLIAM M. DRENNON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,247,077 Caron Nov. 20, 1917 1,484,913 Surry Feb. 26, 1924 2,425,154 Hibbard Aug. 5, 194"! 

